Differential



F. D. KNOBLOCK Aug. 20, 1968 DIFFERENT IAL 4 Sheets-Sheet 1 Filed April 19, 1966 INVENTOR. FREDERICK D. KNOBLOCK fiamwo, M

ATTORNEYS Aug. 20, 1968 F. D. KNOBLOCK DIFFERENTIAL 4 Sheets-Sheet 2 Filed April 19, 1966 Faroemcx D. ii nQl gfi cx W M M ATTORNEYj 0, 1968 F. o KNOBLOCK 3,397,593

DIFFERENTIAL Filed April 19, 1966 4 Sheets-Sheet 4 26 l/ FIG. )5 1 Fla. )8

Fazozmcx D. fifi iock ATTORNEYS United States Patent 3,397,593 DIFFERENTIAL Frederick D. Knoblock, 436 Bonnie Brier, Birmingham, Mich. 48009 Continuation-impart of application Ser. No. 468,717,

July 1, 1965. This application Apr. 19, 1966, Ser.

17 Claims. (Cl. 74650) ABSTRACT OF THE DISCLOSURE The dilferential disclosed herein comprises a driving member and a pair of driven members yieldingly urged together. A center cam is rotatably mounted in the driving member and has circumferentially spaced teeth aligned in one position of the center cam with at least some of the teeth of the driving member. A pair of control cams are rotatably mounted in the driving member and have circumferentially spaced teeth aligned in one position with at least some of the teeth of the driving member. Stop means are provided on the driving member for limiting the rotating movement of each control cam.

This invention is a continuation-in-part of my copending application Ser. No. 468,717, filed July 1, 1965.

This invention relates to differentials and particularly to differentials utilizing interengagin g teeth between the driving and the driven members.

The objects of this invention are to provide a differential which is quiet, cheaper to manufacture, less likely to wear, and foolproof as contrasted to prior differentials of this type.

In the drawings:

FIG. 1 is a sectional view through a differential embodying the invention.

FIG. 2 is a side elevational view of a portion of the differential shown in FIG. 1, parts being broken away.

FIG. 3 is a sectional view taken along the line 33 in FIG. 1.

FIG. 4 is a plan view of a control cam utilized in the differential.

FIG. 5 is a fragmentary sectional view taken along the line 55 in FIG. 4.

FIG. 6 is a plan view of a center cam utilized in the differential.

FIG. 7 is a fragmentary view taken in the direction of the arrow in FIG. 6.

FIG. 8 is a fragmentary plan view of a driven member utilized in the differential.

FIG. 9 is a fragmentary sectional view of a portion of the differential shown in FIG. 1.

FIG. 9a is a fragmentary sectional view similar to FIG. 9 showing some of the parts in further section.

FIGS. 10-13 are fragmentary developed end views showing the relative positions of the parts during operation of the differential.

FIG. 14 is a sectional view similar to FIG. 3 of a modified form of the invention.

FIG. 15 is a fragmentary sectional view of a portion of the differential shown in FIG. 14.

FIG. 16 is a plan view of a center cam utilized in the differential shown in FIGS. 14 and 15.

FIG. 17 is a plan view of a control cam utilized in the differential shown in FIGS. 14 and 15.

FIG. 18 is a fragmentary perspective view showing the relative positions of the driving clutch teeth, control cam and center cam in operating condition of the differential.

Referring to FIG. 1, the differential embodying the invention comprises a separable housing 20 which is adapted to be driven by a bevel gear 21 that meshes with a ring gear 22 fixed to the housing 20. Rotation of the Patented Aug. 20, 1968 "ice housing 20 is adapted to drive the axles 23, 24 as presently described. A driving member 26 in the form of a spider s mounted in the housing 20 for rotation with the housmg. The spider is provided with an annular series of circumferentially spaced teeth 27 on each side thereof which are adapted to engage corresponding teeth 28 on driven members 30, 31.

Each of the driven members 30, 31 is yieldingly urged into position to engage the teeth 28 with the teeth 27 of the driving member 26 by a coil spring 32 which is interposed between a shoulder on the driven members 30, 31 and a retainer 33. Each of the driven members 30, 31 is formed with a spline 34 that meshes with a complementary spline 35 on the shafts 23, 24, respectively.

In operation, when the wheel on one of the axles 23, 24 overruns, the corresponding driven member moves axially out of engagement with the driving member.

Referring to FIGS. 6 and 7, a center cam ring 36 having circumferentially spaced teeth 37 on each side thereon is rotatably mounted within the driving member 26. The teeth 37 are radially aligned, in one position, with alternate teeth 28 of an adjacent driven member 30, 31. Center cam 36 is held in position axially within driving member 26 by control cams 38 on each side of the center cam 36. As shown in FIG. 4, each control cam 38 is formed with circumferentially spaced fingers 39 which extend into an annular groove 40 in the driving member 26 (FIGS. 1, 9) to axially retain the center cam ring 36 in position and, at the same time, axially retain the control cams 38 in position. The control cams 38 are inserted by aligning the fingers 39 of each control cam with slots 40a (FIGS. 3 and 4) in the driving member 26 and rotating the control cam 38 to move the fingers 39 into the groove 40. Slots 40a are so located in driving member 26 that two adjacent slots 40a receive and retain keys 41, 42. These keys 41, 42 retain the cam rings 38 in position and limit their circumferential movement for reasons presently described.

As shown in FIGS. 4 and 5, each of the control cams 38 is formed with circumferentially spaced teeth 43 along each finger 39 so that when the control cam 38 is in one position, the teeth 43 are interposed circumferentially between the adjacent teeth 37 on the center cam 36 and lie substantially in the same plane. In FIG. 3 the teeth 43 are shown aligned with alternate teeth 27 on driving member 26 while the other teeth 27 are aligned with the teeth 37 on center cam ring 36.

As shown in FIG. 8, the teeth 28 on each driven member 30 or 31 extend radially such that the innermost portions or radial extensions 44 thereof intermesh between the cam teeth 37 and 43. As shown in FIG. 7, the teeth 37 of the center cam 36 have inclined sides. The teeth 27. 28 and 43 have beveled edges.

Referring to FIGS. 10-13, in normal operation, for example, when a vehicle utilizing the differential is moving in a straight line, the teeth 27 of the driving member 26 are engaged with the teeth 28 on both of the driven members 30, 31. However, when one of the driven members 31 overruns, for example, when the vehicle is driving around a corner, the member 31 on the outside wheel (FIG. 11) moves ahead of the driving member 26 and some of the teeth 28 engage the inclined sides of the teeth 37 on the center cam 36. As the driven member 31 further overruns the driving member 26, the driven member 31 is cammed outwardly by the inclined sides of the teeth 37 to a position where the teeth 28 overrun the teeth 27 on the driving member.

During this movement, some of the teeth 28 have engaged the teeth 43 on the control cam and rotate the control cam 38 around until rotation is stopped by key 42. In this position, the teeth 43 prevent re-engagement of the teeth 28 on the driven member 31 with the teeth 27 on the driving member as shown in FIG. 12. This condition continues until the driven member 31 no longer overruns the driving member 26. Any slight change in direction of vehicle turning or any slight torque reversal will tend to move the driven member 31 rearwardly, as shown in FIG. 13, causing some of the teeth 28 to engage the teeth 43 and rotate the control cam 38 back away from stop key 42 to its original position. At the same time, the teeth 28 are thereby permitted to move down the inclined sides of the teeth 37 on the center cam 36 into engagement with the teeth 27 on the driving member 31.

A similar operation is achieved when the driven member 30 on the opposite side of the differential overruns. Also when the vehicle is decelerating, or is driving in reverse, the same sequence of events will occur in the opposite direction, with stop key 41 coming into play.

The height of the teeth 43 axially is greater than the height of the teeth 37 which, in turn, is greater than the height of the teeth 27 so that the proper clearances are provided for engagement and re-engagement and for overrunning without successive engagement and re-engagement (FIGS. -13).

In the form of the invention shown in FIGS. 1418, identical reference numerals are used for identical parts. In this form of the invention, the center cam ring 360 (FIG. 16) has circumferentially spaced teeth 370 on each side thereof which have a radial thickness less than the radial width of the main body of the ring 360. The center cam ring 360 is rotatably mounted within the driving member 26 (FIGS. 14, The teeth 370 are radially aligned in one position with teeth 27 of the driving member 26. Center cam 360 is held in position axially within driving member 26 by control cams 380 on each side of the center cam 360. As shown in FIG. 17, each control cam 380 is formed with circumferentially spaced fingers 390 which extend into annular groove 40 (FIG. 15) to axially retain the center cam ring 360 in position and, at the same time, axially retain the control cam 380 in position. The control cams 380 are inserted by aligning the fingers 390 of each control cam 380 with slots 40a (FIG. 14) in the driving member 26 and rotating the control cam 380 to move the fingers 390 into the groove 40. As in the previous design, keys 41, 42 are inserted which retain the cam ring 380 in position and limit their circumferential movement to the desired angle of rotation.

As shown in FIGS. 14, 17 and 18, each of the control cams 380 is formed with circumferentially spaced teeth 430 so that when the control cam 380, center cam 360 and the driving member 26 are in the same position, the teeth 430 are aligned with and located between the teeth 370 on the center cam 360 and the teeth 27 on the driving member 26. The height of the teeth 430 is slightly greater in an axial direction than the height of the teeth 370 which in turn are greater in height than the teeth 27. The teeth 370 of the center cam 360 have inclined sides. The teeth 430 have beveled edges. The teeth 27 extend radially outwardly from the teeth 430 and 370.

The operation of the differential shown in FIGS. 14- 18 is the same as that described above in connection with the form of the invention shown in FIGS. 1-13. Specifically, when a vehicle utilizing the differential is moving in a straight line, the teeth 27 of the driving member 26 are engaged with the teeth 28 on both of the driven members 30, 31. However, when one of the driven members 31 overruns, for example, in going around a corner, the member 31 (FIG. 11) moves ahead of the driving member 26 and some of the teeth 28 engage the inclined sides of the teeth 370 on the center cam 360. As the driven member 31 further overruns the driving member 26, the driven member 31 is cammed outwardly by the inclined sides of the teeth 370 to a position where the teeth 28 overrun the teeth 27 on the driving member.

During this movement, some of the teeth 28 have engaged the teeth 430 on the control cam and carry the control cam 380 around to a position wherein the stop key 42 prevents further rotation of cam 380 (FIG. 12). In this position, the teeth-430 prevent re-engagement of the teeth 28 on the driven member 31 with the teeth 27 on the driving member 26. This condition continues until the driven member 31 no longer overruns the driving member 26. Any slight change in direction of vehicle turning or any slight torque reversal will tend to move the driven member 31 rearwardly with respect to the driving member 26, as shown in FIG. 13, causing some of the teeth 28 to engage the teeth 430 and rotate the control cam 380 away from key 42 back to its original position. At the same time, the teeth 28 are thereby permitted to move down the inclined sides of the teeth 370 on the center cam 360 into engagement with the teeth 27 on the driving member 31 as in FIG. 10.

A similar operation is achieved when the driven member 30 on the opposite side of the differential overruns. Also, if motor torque reverses and either driven member 30 or 31 underruns the driving member 26, then its control cam 430 will be rotated in the other direction until it is stopped by key 41. Then all events will follow as before but in this direction of rotation.

It can thus be seen that there has been provided a dif ferential which is relatively quiet, is cheaper to manufacture because of a lesser number of parts, and which requires no thrust members other than the control cam.

I claim:

1. A difierential comprising a driving member,

a pair of driven members,

means yieldingly urging said driven members and said driving member together,

interengaging teeth between said driving member and said driven members,

a center cam rotatably mounted in said driving member,

said center cam having circumferentially spaced teeth aligned in one position of said center cam with at least some of the teeth of said driving member,

a pair of control cams rotatably mounted in said driving member, each said control cam having circumferentially spaced teeth aligned in one position of said control cam with at least some of the teeth of the driving member,

means on the driving member for limiting the rotating movement of each said control cam,

whereby when one of said driven members overruns said driving member, the teeth on said driven member are moved out of engagement with the teeth on said driving member by the teeth on said center cam and said control cam is rotated circumferentially to a position which prevents re-engagement of the teeth of the overrunning driven member with the teeth of the driving'member.

2. The combination set forth in claim 1 wherein the teeth on each control cam have a lesser circumferential width than the teeth on said center cam.

3. The combination set forth in claim 1 wherein the edges of said control cam teeth are beveled.

4. The combination set forth in claim 1 wherein the circumferentially spaced teeth of each said control cam are always circumferentially interposed between the teeth of the center cam.

5. The combination set forth in claim 1 wherein the height of the teeth on the control cam is greater than the height of the teeth on the center cam and the height of the teeth on the center cam being greater than the height of the teeth on the driving member.

6. The combination set forth in claim 5 wherein the teeth on each control cam have a lesser circumferential width than the teeth on said center cam.

7. The combination set forth in claim 6 wherein the edges of all said teeth are beveled.

8. The combination set forth in claim 1 wherein the circumferentially spaced teeth on the center cam are aligned in said one position of said center cam with alternate teeth of the driving member.

9. A difierential comprising a driving member,

a pair of driven members,

means yieldingly urging said driven members toward said driving members,

interengaging teeth between said driving member and said driven members,

a center cam rotatably mounted in said driving member,

said center cam having circumferentially spaced teeth aligned in one position of said center cam with some of the teeth of said driving member,

a pair of control cams rotatably mounted in said driving member,

each said control cam having circumferentially spaced teeth interposed between the teeth of said center cam and aligned in one position of said control cam with other of the teeth of the driving member,

stop means on the driving member for limiting the angular movement of said control cam,

whereby when one of said driven members overruns said driving member, the teeth on said driven member are moved out of engagement with the teeth on said driving member by the teeth on said center cam and said control cam adjacent said overrunning driven member is rotated circumferentially to a position which prevents re-engagement of the overrunning driven member with the teeth of the driving member.

10. A diiferential comprising a driving member,

a pair of driven members,

means yieldingly urging said driven members toward said driving member,

interengaging teeth between said driving member and said driven members,

a center cam rotatably mounted in said driving member,

said center cam 'having circumferentially spaced teeth aligned in one position of said center cam with alternate teeth of said driving member,

a pair of control cams rotatably mounted in said driving member,

each said control cam having circumferentially spaced teeth interposed between the teeth of said center cam and aligned in one position of said control cam with alternate teeth of the driving member,

stop means on said driving member for limiting the angular movement of said control cam,

said teeth on said driven members having radial inwardly directed extensions engaging between the teeth of said center cam and control cams,

the height of the teeth on the control cam being greater than the height of the teeth on the center cam and the teeth on the driving member,

the height of the teeth on the center cam being greater than the height of the teeth on the driving member,

said teeth on said center cam having inclined sides,

whereby when one of said driven members overruns said driving member, the teeth on said driven member are moved out of engagement with the teeth on said driving member by engagement with the inclined sides of the teeth on said center cam and said control cam adjacent said driven member is rotated circumferentially to a position which prevents re-engagement of the overrunning driven member with the teeth of the driving member.

11. A differential comprising a driving member,

a pair of driven members,

means yieldingly urging said driven members and said driving member together,

interengaging teeth between said driving member and said driven members,

a center cam rotatably mounted in said driving member,

said center cam having circumferentially spaced teeth aligned in one position of said center cam with at least some of the teeth of said driving member,

a pair of control cams rotatably mounted in said driving member,

each said control cam having circumferentially spaced teeth aligned in one position of said control cam with at least some of the teeth of the driving member,

stop means on said driving member for limiting the angular movement of each said control cam,

the circumferentially spaced teeth of each said control cam being aligned in one position of said control c-arn with other of said teeth of the center cam,

the circumferentially spaced teeth of each control cam being radially interposed between the teeth on said driving member and the teeth on said center cam,

the height of the teeth on the control cam being greater than the height of the teeth on the center cam and the height of the teeth on the center cam being greater than the height of the teeth on the driving member,

whereby when one of said driven members overruns said driving member, the teeth on said driven member are moved out of engagement with the teeth on said driving members by the teeth on said center cam and said control cam is rotated circumferentially to a position which prevents re-engage'ment of the teeth of the overrunning driven member with the teeth of the driving member.

12. A differential comprising a driving member,

a pair of driven members,

means yieldingly urging said driven members and said driving member together,

interengaging teeth between said driving member and said driven members,

a center cam rotatably mounted in said driving member,

said center cam having circumferentially spaced teeth aligned in one position of said center cam with some of the teeth of said driving member,

a pair of control cams rotatably mounted in said driving member,

each said control cam having circumferentially spaced teeth aligned in one position of said control cam with other of the teeth of the driving member,

means on the driving member for limiting the rotating movement of each said control cam,

whereby dhen one of said driven members overruns said driving member, the teeth on said driven member are moved out of engagement with the teeth on said driving member by the teeth on said center cam and said control cam is rotated circumferen-tially to a position which prevents re-engagement of the teeth of the overrunning driven member with the teeth of the driving member,

the circumferentially spaced teeth of each control cam being radially interposed between the teeth on said driving member and the teeth on said center cam.

13. A diiferential comprising a driving member,

a pair of driven members,

means yieldingly urging said driven members and said driving member together,

interengaging teeth between said driving member and said driven members,

a center cam rotatably mounted in said driving member,

said center cam having circumferentially spaced teeth aligned in one position of said center cam with some of the teeth of said driving member,

a pair of control cams rotatably mounted in said driving member,

each said control cam having circumferentially spaced teeth aligned in one position of said control cam with other of the teeth of the driving member,

means on the driving member for limiting the rotating movement of each said control cam,

whereby when one of said driven members overruns said driving member, the teeth on said driven member are moved out of engagement with the teeth on said driving member by the teeth on said center cam and said control cam is rotated circumferentially to a position which prevents re-engagement of the teeth of the overrunning driven member With the teeth of the driving member,

said teeth on said driven members having radial extensions engaging between the teeth of said center cam and control cams.

14. The combination set forth in claim 10 wherein the teeth on each control cam have a lesser circumferential Width than the teeth on said center cam.

15. The combination set forth in claim 10 wherein the edges of said control cam teeth are beveled.

16. The combination set forth in claim 11 wherein the teeth on each control cam have a lesser circumferential Width than the teeth on said center cam.

17. The combination set forth in claim 11 wherein the 5 edges of said control cam teeth are beveled.

References Cited UNITED STATES PATENTS 10 2,329,059 9/1943 Knoblock 74650 2,638,794 5/1953 Knoblock 74650 2,667,087 1/1954 Myers 74650 2,830,466 4/1958 Myers 74650 15 FRED C. MATPERN, JR., Primary Examiner.

ARTHUR T. MCKEON, Assistant Examiner. 

